The present invention relates generally to brake systems for automotive vehicles, and more particularly, to an emergency brake assist system.
Automotive brake systems are the result of a long evolutionary process and are one of the most important systems in a vehicle. Typical brake systems include a master cylinder, located under the hood, which is directly connected to a brake pedal. The master cylinder converts mechanical pressure applied to the brake pedal into a proportional amount of hydraulic pressure. This hydraulic pressure is used to actuate the vehicle brakes. Many brake systems also use the engine""s energy to add pressure to the master cylinder.
To improve upon standard braking systems, various automatic braking systems have been suggested in the prior art. U.S. Pat. No. 6,189,987 describes a brake force control apparatus which cannot generate an unnecessarily large brake force when an emergency brake is performed while a vehicle is traveling on a rough road or riding over a step.
The ""987 patent is equipped with a fluid pressure generating mechanism, which generates an assist hydraulic pressure in which a pump is used as a fluid pressure source. The fluid pressure generating mechanism generates the assist hydraulic pressure based on a driving signal supplied from a control circuit. When the brake pedal is operated at a speed higher than a predetermined speed, the control circuit determines that an emergency braking is carried out by the driver, and outputs to the fluid pressure generating mechanism a drive signal which requests a maximum assist hydraulic pressure.
However, besides a situation in which the driver intentionally performs the emergency braking, the brake pedal may be pressed at a high speed if the vehicle is traveling on a rough road or the vehicle rides over a step on the road. According to the above conventional apparatus, the brake assist control is performed without exception when the brake pedal is depressed at a speed equal to or higher than the predetermined value irrespective of the vehicle traveling environment. Hence, the conventional apparatus may generate an unnecessarily large braking force when the vehicle is traveling on a rough road or passing a step.
Additionally, recent data indicates that some drivers do not apply all available braking force during emergency situations. This phenomenon occurs even when a collision is imminent. The system described in the ""987 patent is still very reliant upon the actions of the driver.
The disadvantages associated with these conventional automatic emergency braking techniques have made it apparent that a new technique for automatic emergency braking is needed. The new technique should reduce crash energy in frontal collisions while enhancing driver performance. The present invention is directed to these ends.
It is, therefore, an object of the invention to provide an improved and reliable emergency brake assist system.
In accordance with the objects of this invention, an emergency brake assist apparatus amplifies driver braking force upon imminent contact detection. A brake pedal, operated by the driver, exerts a pedal force upon a variable brake booster. A braking system is coupled to the variable brake booster that produces a variable brake booster force causing the braking system to exert a braking force proportional to the pedal force during normal operation. When a forward detection apparatus detects an imminent contact, a controller signals the variable brake booster to increase the variable brake booster force such that the braking system exerts an amplified braking force proportional to the pedal force.
The present invention thus achieves an improved emergency brake assist system. The present invention is advantageous in that it enhances driver braking performance during imminent contact situations. Additionally, the present invention maintains prior art braking levels when an occupant is unbelted.
Additional advantages and features of the present invention will become apparent from the description that follows, and may be realized by means of the instrumentalities and combinations particularly pointed out in the appended claims, taken in conjunction with the accompanying drawings.